Which dry ready concrete for strong bollards?
- Thread starter Oker
- Start date
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Oker,
All and any of those pre mixed concrete bags that you suggested will work to make concrete, expect for any labeled 'postcrete' which will set too fast (it is used to set posts in the ground, not make posts). For your application they all make concrete of about the same strength.
For a link here is a strong 40N concrete from Wickes which as said before can be delivered:
https://www.wickes.co.uk/Hanson-40N-Ready-Mixed-Concrete-Maxi-Bag---20kg/p/137250
The issue is that I doubt anyone will 'recommend' any type of concrete to make a steel reinforced 20x20x100cm=96kg (+ the length to go in the ground) concrete bollard to protect your tree for the reasons that were provided before. Especially when there are metal bollards (and even pre-made concrete lintels) that will be better suited for the job and likely cheaper than the 96kg of concrete, wood mold you need per bollard.
SFK
All and any of those pre mixed concrete bags that you suggested will work to make concrete, expect for any labeled 'postcrete' which will set too fast (it is used to set posts in the ground, not make posts). For your application they all make concrete of about the same strength.
For a link here is a strong 40N concrete from Wickes which as said before can be delivered:
https://www.wickes.co.uk/Hanson-40N-Ready-Mixed-Concrete-Maxi-Bag---20kg/p/137250
The issue is that I doubt anyone will 'recommend' any type of concrete to make a steel reinforced 20x20x100cm=96kg (+ the length to go in the ground) concrete bollard to protect your tree for the reasons that were provided before. Especially when there are metal bollards (and even pre-made concrete lintels) that will be better suited for the job and likely cheaper than the 96kg of concrete, wood mold you need per bollard.
SFK
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I do not have any other option. I have to do what I said. Because under the land (about 20 cm) is a very heavy flat metal with very narrow slits. I will put 4 rebars one meter deep into the slits for each bollards. But the concrete will be only 20 cm deep which is not good.
Because I cannot put very deep all ready made bollards, I have to do what I said. Or do you have any other idea?
Because I cannot put very deep all ready made bollards, I have to do what I said. Or do you have any other idea?
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Only 20cm of foundations does make it very difficult.
I would be tempted go for a shorter concrete or steel bollard - say 60cm with only 40cm sticking out of ground.
Only because the longer it is the more likely it will be simply cracked / snapped when it is eventually hit.
Other (ugly) solution is get some 100mm dia waste pipe, or scafolding tube, put it over your rebar that is in the ground and fill with concrete. Thenput concrete around bottom for foundation. That will minimise cracking issues and save time on making a wood mold box.
SFK
I would be tempted go for a shorter concrete or steel bollard - say 60cm with only 40cm sticking out of ground.
Only because the longer it is the more likely it will be simply cracked / snapped when it is eventually hit.
Other (ugly) solution is get some 100mm dia waste pipe, or scafolding tube, put it over your rebar that is in the ground and fill with concrete. Thenput concrete around bottom for foundation. That will minimise cracking issues and save time on making a wood mold box.
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you could use large flowerpots or planters. When full of earth they are extremely heavy and will resist impact from a vehicle. Because they do not look very unsightly they are used around the world to protect embassies and government buildings from truck bomb attacks.
Because they rely on mass they do not have to be concreted into place.
they are not too heavy to drag around when empty, so they are fairly easy to work with. If you wish, you can fill them with bricks or rubbles, then soil. The plant roots will find their way between the rubble. You can get plastic ones or concrete ones. Both can be painted with masonry paint to make them stand out or blend in, according to your needs. If you ever need to move one, you can dig out the filling and barrow it away. If you don't like gardening you can put in dummy plants or bushes.
Because they rely on mass they do not have to be concreted into place.
they are not too heavy to drag around when empty, so they are fairly easy to work with. If you wish, you can fill them with bricks or rubbles, then soil. The plant roots will find their way between the rubble. You can get plastic ones or concrete ones. Both can be painted with masonry paint to make them stand out or blend in, according to your needs. If you ever need to move one, you can dig out the filling and barrow it away. If you don't like gardening you can put in dummy plants or bushes.
Oker,
And I would also repeat, that If you expect that bollard will be hit by a car or by a lorry, it might be best to have a lightweight steel bollard with 20cm foundations.
It will be knocked down, but it will be easy to put back up again.
If you over engineer your bollards, they will still be knocked down or bent, AND they will then be a nightmare to remove and reinstall.
SFK
And I would also repeat, that If you expect that bollard will be hit by a car or by a lorry, it might be best to have a lightweight steel bollard with 20cm foundations.
It will be knocked down, but it will be easy to put back up again.
If you over engineer your bollards, they will still be knocked down or bent, AND they will then be a nightmare to remove and reinstall.
SFK
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Great idea from JohnD.
He has reminded me that we used flower planters one third filled with bricks.
They can be moved with some effort, but cars be damaged by them and so will have to stop before hitting the tree.
You could also put your rebar into the ground to stake them in place.
SFK
He has reminded me that we used flower planters one third filled with bricks.
They can be moved with some effort, but cars be damaged by them and so will have to stop before hitting the tree.
You could also put your rebar into the ground to stake them in place.
SFK
Or use a large rock:
https://www.reddit.com/r/IdiotsInCa...al_donut_shop_put_a_rock_in_their_planter_to/
https://www.reddit.com/r/IdiotsInCa...al_donut_shop_put_a_rock_in_their_planter_to/
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